package datastructure.algorithm;

public class Recursion {
	int sum = 0;
	void abc(int n){
		if(n==0)
			return;
		sum += n;
		abc(--n);
	}
	
	long abcd(int n){
		long a=0;
		for(int i=1;i<=n;i++)
			a += i;
		return a;
	}
	public static void main(String[] args) {
		Recursion a = new Recursion();
//		a.abc(10000);
//		System.out.println(a.sum);
		System.out.println(a.abcd(2000000000));
	}

}
